Spear gun fishing by underwater divers involves the use of a gun that propels a spear towards a fish. When the spear pierces the fish, the fish usually flips and turns through violent contortions to free itself of the spear. Unless the spear tip is fashioned with devices to prevent it from being retracted from the fish, the spear may be shaken loose by the contortions of the fish and the catch is lost. Spear tips of the prior art included some type of barb which was broader at its base than near the point so that reverse movement of the barb is inhibited. One type of prior art spear tip incorporates two pivotable wings which collapse against the shaft as the spear point passes through the fish, but which pivot outwardly upon any reverse movement of the shaft to allegedly prevent retraction of the spear point through the same hole it entered. This tip is removable from the spear shaft by unscrewing the screw thread connection between the tip and shaft so as to recover the shaft and tip from the fish. A second type of prior art spear tip included a tip with a flared base to prevent its retraction through the entry hole. The spear, however, could be detached from the spear point by merely pulling the two portions apart as by a fish pulling against the tip. The two portions are connected by a length of cord so as not to lose either portion. Neither of thse types of spear tips are completely satisfactory because they are not easily recovered from the fish and the tips have to be fed back through the hole in the fish. Also, often the hole in the fish "wallows" out and often the tip feeds itself back into the hole and the fish is lost and/or tip becomes lodged laterally within the fish making it difficult to remove without materially damaging the fish.
In parent applications Ser. Nos. 072,297 and 171,018 cited above, there are disclosed two alternative designs of spear tip assemblies that can be slidably attached to the forward end of the shaft of a spear, the tip assembly being removable after spearing a fish and can be replaced by a second such tip assembly or the original tip assembly can be removed from the speared fish and reused.
It is an object of this invention to provide still another improved tip assembly for a spear shaft used in underwater fishing. It is another object of this invention to provide an extension tip assembly to be used with an improved type of spear tip, which is easily assembled and readily removed from the fish for reassembly. Still other objects are to provide a tip assembly which alleviates the aforementioned problems of the prior art as will become apparent from the more detailed description which follows.